Capillary zone electrophoresis for simultaneous determination of seven nonsteroidal anti-inflammatory drugs in pharmaceuticals

Rapid and sensitive determination of Piroxicam by N-doped carbon dots prepared by plant soot

Piroxicam (PX) as a nonsteroidal anti-inflammatory drug (NSAID) can be effectively used for anti-inflammatory and analgesia. However, overdoses may induce side effects such as gastrointestinal ulcers and headaches. Therefore, the assay of piroxicam has considerable significance. In this work, nitrogen-doped carbon dots (N-CDs) was synthesized for PX detection. The fluorescence sensor was fabricated by hydrothermal method with plant soot and ethylenediamine. The strategy exhibited a detection range of 6-200 μg/mL and 250-700 μg/mL with the limited detection of 2 μg/mL. The mechanism of the PX assay base on the fluorescence sensor was the process of electron transfer between the PX and N-CDs. The assay subsequently demonstrated could be successfully used in actual sample. The results indicated that the N-CDs could be a superior candidate nanomaterial for piroxicam monitoring in the healthcare product industry.

Efficient determination of non-steroidal anti-inflammatory drugs by micellar electrokinetic chromatography in wastewater

Recently, non-steroidal anti-inflammatory drugs (NSAIDs) have been increasingly used in humans and animals. Despite being effective against a wide variety of diseases, they pose a threat to aquatic environments. In the current work, a highly efficient, selective, and sensitive micellar electrokinetic chromatography (MEKC) method was developed for the determination of five NSAIDs in environmental water samples. The optimal separation BGE was 15 mM borate buffer (pH 9), 90 mM SDS, and 10% methanol at a separation voltage of 15 kV and a hydrodynamic injection of 10 mbar for 5 s. The results presented in this study provide a higher number of theoretical plates N > 780 000 with excellent RSDs of 0.1-1.5% and great sensitivity (3-15 μg L^-1) for NSAIDs. To validate this method, the solid phase extraction method was optimized using two different cartridges (C18 and Oasis HLB); the results showed excellent recoveries (73-111.6%) for all the analytes in wastewater samples.

A novel molecularly imprinted electrochemical sensor based on a nitrogen-doped graphene oxide quantum dot and molybdenum carbide nanocomposite for indometacin determination

In this work, nitrogen-doped graphene oxide quantum dots (N-GOQDs) were embedded into Mo₂C to prepare a nanocomposite with great electrical conductivity and a large specific surface area. We manufactured an innovative electrochemical sensor based on N-GOQDs-Mo₂C and a molecularly imprinted polymer (MIP) for the highly sensitive detection of indometacin (IDMC). The MIP was synthesized by electropolymerization using acrylamide as the functional monomer and IDMC as the template molecule. N-GOQDs-Mo₂C was organized by an elementary hydrothermal approach and characterized by SEM, TEM, XRD and FT-IR. In the first-rank experimental conditions, the MIP electrochemical sensor shows a wide linear range from 10^-15 M to 10^-5 M for IDMC detection and the detection limit is as low as 9.508 × 10^-16 M. Additionally, the manufactured sensor shows great selectivity for indometacin, excellent repeatability and stableness. The sensor can be applied to the detection of indometacin in tablets and water samples with fulfilling consequence.

Potential of microchip electrophoresis in pharmaceutical analysis: Development of a universal method for frequently prescribed nonsteroidal anti-inflammatory drugs

A novel microchip electrophoresis method with conductivity detection for the determination of nonsteroidal anti-inflammatory drugs (NSAIDs) in several pharmaceutical formulations was developed. The three frequently used NSAIDs - acetylsalicylic acid, diclofenac and ibuprofen were baseline separated on a poly(methyl methacrylate) microchip with coupled separation channels. Elimination of matrix components such as excipients, was realized through online combination of isotachophoresis (ITP) with zone electrophoresis (ZE). ITP-ZE hyphenation can also facilitate preconcentration of target analytes. ITP was carried out in the first separation channel at pH 6.5, while the second channel of the microchip was used for ZE separation and detection of the analytes at pH 7.0. The developed ITP-ZE method was demonstrated to be applicable for direct and reliable determination of NSAIDs in eleven pharmaceutical formulations. The noticeable advantage of this approach is that only simple sample pretreatment (filtration and dilution) is necessary. The method performance parameters, such as linearity (20-250% of nominal concentration of studied NSAIDs in the test samples), accuracy (98-102%) and precision (less than 2% RSD) were obtained. This universal approach is suitable for the determination of frequently used NSAIDs in a single analysis in less than 15 min. In addition to simple sample pretreatment, low running costs and minimal environmental impact could make this method attractive for the analysis of pharmaceutical preparations.

Synthesis and electrochemical properties of environmental free l-glutathione grafted graphene oxide/ZnO nanocomposite for highly selective piroxicam sensing

A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite (glutathione-GO/ZnO) as electrode material for the high-performance piroxicam sensor. The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam (oxidation potential is 0.52 V). Under controlled experimental parameters, the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 μM. The detection limit and sensitivity were calculated as 1.8 nM and 0.2 μA/μM·cm2, respectively. Moreover, it offered excellent selectivity, reproducibility, and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration. Finally, the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.

Molecularly Imprinted Micelles for Fluorescent Sensing of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used over-the-counter drugs and their uncontrolled disposal is a significant environmental concern. Although their fluorescent sensing is a desirable method of detection for its sensitivity and simplicity, the structural similarity of the drugs makes the design of selective sensors highly challenging. A thiourea-based fluorescent functional monomer was identified in this work to enable highly efficient synthesis of molecularly imprinted nanoparticle (MINP) sensors for NSAIDs such as Indomethacin or Tolmetin. Micromolar binding affinities were obtained in aqueous solution, with binding selectivities comparable to those reported for polyclonal antibodies. The detection limit was ~50 ng/mL in aqueous solution, and common carboxylic acids such as acetic acid, benzoic acid, and citric acid showed negligible interference.

Piroxicam

A comprehensive profile of piroxicam including the nomenclatures, formulae, elemental composition, appearance, uses and applications. The methods which were utilized for the preparation of the drug substance and their respective schemes are outlined. The physical characteristics of the drug including the ionization constant, solubility, x-ray powder diffraction pattern, differential scanning calorimetry, thermal behavior and spectroscopic studies are described. The methods which were used for the analysis of the drug substance in bulk drug and/or in pharmaceutical formulations including the compendial, spectrophotometric, electrochemical and the chromatographic methods are reported. The stability, toxicity, pharmacokinetics, bioavailability, drug evaluation, comparison, in addition to compiled reviews on the drug substance are involved. Finally, more than four hundred and fifty references are listed at the end of this profile.

Sensitive Electrochemical Monitoring of Piroxicam in Pharmaceuticals Using Carbon Ionic Liquid Electrode

Background:

Piroxicam is a non-steroidal anti-inflammatory drug. The prevailing clinical use and investigation of piroxicam necessitate a rapid and sensitive method for its determination. A carbon ionic liquid electrode, fabricated using graphite and the ionic liquid 1-octylpyridinium hexafluorophosphate (OPFP) was used as an electrochemical sensor for piroxicam determination.

Methods:

The surface of the proposed electrode was characterized by scanning electron microscopy. Cyclic voltammetry (CV) was applied to study the oxidation of piroxicam and to acquire information about the reaction mechanism. Differential pulse voltammetry was also used as an analytical technique for quantification of the sub-micromolar concentration of piroxicam.

Results:

One oxidation peak at 0.55V was observed at CILE. The oxidation peak at the CPE was weak, while the response was notably increased at the CILE. The proposed electrode exhibited interesting sensitivity towards the determination of piroxicam and the anodic peak current versus piroxicam concentration was linear in the ranges of 0.2-60 µM. The detection limit of 40 nM was achieved.

Conclusion:

The electroxidation process was irreversible and revealed adsorption controlled behavior. The method was successfully applied for the determination of piroxicam content in pharmaceutical samples.

Three hidden talents in one framework: a terephthalic acid-coordinated cupric metal–organic framework with cascade cysteine oxidase- and peroxidase-mimicking activities and stimulus-responsive fluorescence for cysteine sensing

A terephthalic acid-coordinated cupric metal–organic framework with cascade cysteine oxidase- and peroxidase-mimicking activities and stimulus-responsive fluorescence for cysteine sensing.

Simultaneous preconcentration of polar and non-polar organophosphorus pesticides from water samples by using a new sorbent based on mesoporous silica

A new mesoporous silica based on the sol-gel material cyanopropyltriethoxysilane (CNPrTEOS) was successfully synthesized by the hydrolysis and condensation of CNPrTEOS in the presence of ammonium solution as catalyst and methanol as solvent. It was used as a solid-phase extraction sorbent for the simultaneous extraction of three organophosphorus pesticides, namely, polar dicrotophos and non-polar diazinon and chlorpyrifos. Analysis was performed using high-performance liquid chromatography with UV detection. CNPrTEOS was characterized by FTIR spectroscopy, field-emission scanning electron microscopy and nitrogen gas adsorption. The surface area and average pore diameter of the optimum sol-gel CNPrTEOS are 379 m(2) /g and 4.7 nm (mesoporous), respectively. The proposed solid-phase extraction based on CNPrTEOS exhibited good linearity in the range of 0.8-100 μg/L, satisfactory precision (1.15-3.82%), high enrichment factor (800) and low limit of detection (0.072-0.091 μg/L). The limits of detection obtained using the proposed solid-phase extraction method are well below the maximum residue limit set by European Union and are also lower (13.6-48.5×) than that obtained by using a commercial CN-SPE cartridge (0.98-4.41 μg/L). The new mesoporous sol-gel CNPrTEOS showed promising alternative as SPE sorbent material for the simultaneous extraction of polar and non-polar organophosphorus pesticides.

Validated method for the determination of piroxicam by capillary zone electrophoresis and its application to tablets

Simple and rapid capillary zone electrophoretic method was developed and validated in this study for the determination of piroxicam in tablets. The separation of piroxicam was conducted in a fused-silica capillary by using 10 mM borate buffer (pH 9.0) containing 10% (v/v) methanol as background electrolyte. The optimum conditions determined were 25 kV for separation voltage and 1 s for injection time. Analysis was carried out with UV detection at 204 nm. Naproxen sodium was used as an internal standard. The method was linear over the range of 0.23-28.79 µg/mL. The accuracy and precision were found to be satisfied within the acceptable limits (<2%). The LOD and LOQ were found to be 0.07 and 0.19 µg/mL, respectively. The method described here was applied to tablet dosage forms and the content of a tablet was found in the limits of USP-24 suggestions. To compare the results of capillary electrophoretic method, UV spectrophotometric method was developed and the difference between two methods was found to be insignificant. The capillary zone electrophoretic method developed in this study is rapid, simple, and suitable for routine analysis of piroxicam in pharmaceutical tablets.

Quantitative analysis of piroxicam using temperature-controlled ionic liquid dispersive liquid phase microextraction followed by stopped-flow injection spectrofluorimetry

BACKGROUND

Piroxicam (PXM) belongs to the wide class of non-steroidal anti-inflammatory drugs (NSAIDs). PXM has been widely applied in the treatment of rheumatoid arthritis, gonarthrosis, osteoarthritis, backaches, neuralgia, mialgia. In the presented work, a green and benign sample pretreatment method called temperature-controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME) was followed with stopped-flow injection spectrofluorimetry (SFIS) for quantitation of PXM in pharmaceutical formulations and biological samples.

METHODS

Temperature-controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME) was applied as an environmentally friendly sample enrichment method to extract and isolate PXM prior to quantitation. Dispersion of 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6]) ionic liquid (IL) through the sample aqueous solution was performed by applying a relatively high temperature. PXM was extracted into the extractor, and after phase separation, PXM in the final solution was determined by stopped-flow injection spectrofluorimetry (SFIS).

RESULTS AND MAJOR CONCLUSION

Different factors affecting the designed method such as IL amount, diluting agent, pH and temperature were investigated in details and optimized. The method provided a linear dynamic range of 0.2-150 μg l-1, a limit of detection (LOD) of 0.046 μg l-1 and a relative standard deviation (RSD) of 3.1%. Furthermore, in order to demonstrate the analytical applicability of the recommended method, it was applied for quantitation of PXM in real samples.

Pulse perturbation technique for determination of piroxicam in pharmaceuticals using an oscillatory reaction system

A simple and reliable novel kinetic method for the determination of piroxicam (PX) was proposed and validated. For quantitative determination of PX, the Bray-Liebhafsky (BL) oscillatory reaction was used in a stable non-equilibrium stationary state close to the bifurcation point. Under the optimized reaction conditions (T = 55.0°C, [H2SO4]0 = 7.60×10−2 mol L−1, [KIO3]0 = 5.90×10−2 mol L−1, [H2O2]0 = 1.50×10−1 mol L−1 and j 0 = 2.95×10−2 min−1), the linear relationship between maximal potential shift ΔE m , and PX concentration was obtained in the concentration range 11.2–480.5 µg mL−1 with a detection limit of 9.9 µg mL−1. The method had a rather good sample throughput of 25 samples h−1 with a precision RSD = 4.7% as well as recoveries RCV ≤ 104.4%. Applicability of the proposed method to the direct determination of piroxicam in different pharmaceutical formulations (tablets, ampoules and gel) was demonstrated.

Selective micellar electrokinetic chromatographic method for simultaneous determination of some pharmaceutical binary mixtures containing non-steroidal anti-inflammatory drugs

A simple and selective micellar electrokinetic chromatographic (MEKC) method has been developed for the analysis of five pharmaceutical binary mixtures containing three non-steroidal anti-inflammatory drugs (NSAIDs). The investigated mixtures were Ibuprofen (IP)–Paracetamol (PC), Ibuprofen (IP)–Chlorzoxazone (CZ), Ibuprofen (IP)–Methocarbamol (MC), Ketoprofen (KP)–Chlorzoxazone (CZ) and Diclofenac sodium (DS)–Lidocaine hydrochloride (LC). The separation was run for all mixtures using borate buffer (20 mM, pH 9) containing 15% (v/v) methanol and 100 mM sodium dodecyl sulphate (SDS) at 15 kV and the components were detected at 214 nm. Different factors affecting the electrophoretic mobility of the seven investigated drugs were studied and optimized. The method was validated according to international conference of harmonization (ICH) guidelines and United States pharmacopoeia (USP). The method was applied to the analysis of five pharmaceutical binary mixtures in their dosage forms. The results were compared with other reported high performance liquid chromatographic methods and no significant differences were observed.

Sequential injection analysis (SIA)-chemiluminescence determination of indomethacin using tris[(2,2′-bipyridyl)]ruthenium(III) as reagent and its application to semisolid pharmaceutical dosage forms

Automated sequential injection (SIA) method for chemiluminescence (CL) determination of nonsteroidal anti-inflammatory drug indomethacin (I) was devised. The CL radiation was emitted in the reaction of I (dissolved in aqueous 50% v/v ethanol) with intermediate reagent tris(2,2'-bipyridyl)ruthenium(III) (Ru(bipy)(3)(3+)) in the presence of acetate. The Ru(bipy)(3)(3+) was generated on-line in the SIA system by the oxidation of 0.5mM tris(2,2'-bipyridyl)ruthenium(II) (Ru(bipy)(3)(2+)) with Ce(IV) ammonium sulphate in diluted sulphuric acid. The optimum sequence, concentrations, and aspirated volumes of reactant zones were: 15 mM Ce(IV) in 50mM sulphuric acid 41 microL, 0.5 mM Ru(bipy)(3)(2+) 30 microL, 0.4M Na acetate 16 microL and I sample 15 microL; the flow rates were 60 microLs(-1) for the aspiration into the holding coil and 100 microLs(-1) for detection. Calibration curve relating the intensity of CL (peak height of the transient CL signal) to concentration of I was curvilinear (second order polynomial) for 0.1-50 microM I (r=0.9997; n=9) with rectilinear section in the range 0.1-10 microM I (r=0.9995; n=5). The limit of detection (3sigma) was 0.05 microM I. Repeatability of peak heights (R.S.D., n=10) ranged between 2.4% (0.5 microM I) and 2.0% (7 microM I). Sample throughput was 180 h(-1). The method was applied to determination of 1 to 5% of I in semisolid dosage forms (gels and ointments). The results compared well with those of UV spectrophotometric method.

Direct chemiluminescence determination of ibuprofen by the enhancement of the KMnO4–sulphite reaction

A simple, rapid, flow-injection chemiluminescence (CL) method is described for the determination of ibuprofen. A strong CL signal was detected when a mixture of the analyte and sulphite was injected into acidic KMnO(4). The CL signal is proportional to the concentration of ibuprofen in the range 0.1-10.0 mg/L. The detection limit is 0.02 mg/L ibuprofen, the relative standard deviation is 1.8% (0.5 mg/L ibuprofen; n = 11) and the sample measurement frequency is 120/h. The proposed method was successfully applied to the determination of ibuprofen in pharmaceutical preparations and in spiked urine samples. The mechanism of the CL reaction is also discussed.

Flow injection chemiluminescence determination of naproxen based on KMnO4–Na2SO3 reaction in neutral aqueous medium

A simple, rapid and sensitive flow injection chemiluminescence (CL) method is described for the determination of naproxen. It was found that strong CL signal was generated when naproxen was mixed with KMnO4 and Na2SO3 in neutral aqueous medium. Under the optimum experimental conditions, the CL intensity was linearly related to the concentration of naproxen from 4.0 x 10(-9) to 1.0 x 10(-6)g mL(-1) (r=0.9993). The detection limit was 2 x 10(-9)g mL(-1) naproxen, the relative standard deviation for 1.0 x 10(-7) g mL(-1) naproxen solution was 1.5% (n=11) and the sampling frequency was 120 h(-1). The method was applied to the determination of naproxen in pharmaceutical preparation with satisfactory results. The mechanism of CL reaction was discussed briefly.

Capillary electrophoresis combining field-amplified sample stacking and electroosmotic flow suppressant for analysis of sulindac and its two metabolites in plasma

Field-amplified sample stacking with electroosmotic flow (EOF) suppressant in capillary electrophoresis was used to determine the concentration of sulindac (SU) and its two active metabolites, sulindac sulfide (SI) and sulindac sulfone (SO), in human plasma. After acidification, the analytes were extracted from the plasma with dichloromethane. Before sample loading, a water plug (0.5 psi, 3 s) was injected to contain sample anions and to permit field-amplified stacking. Electrokinetic injection at a reversed voltage (-6 kV, 99.9 s) was then used to introduce anions. Separation was performed using phosphate buffer (80 mM, pH 6.0) containing 2,6-di-O-methyl-beta-cyclodextrin (0.75 mM), and poly(ethylene oxide) (0.01%) as an EOF suppressant. The separation was performed at -30 kV and 200 nm. During method validation, calibration plots were linear (r > 0.994) over a range of 0.3-30.0 microM for SU and SO, and 0.5-30.0 microM for SI. During intra- and inter-day analysis, relative standard deviations (RSD) and relative errors (RE) were all less than 16%. The limits of detection were 0.1 microM for SU and SO, and 0.3 microM for SI (S/N = 4, sampling 99.9s at -6 kV). This method was feasible for determining SU and its metabolites in plasma. One female volunteer (27 years, 42 kg) was orally administered one SU tablet (Clinoril, 20 0 mg/tab), and blood samples were drawn at regular intervals over an 8h period. After pretreatment and analysis, the plasma levels of SU, SI and SO were monitored. The pharmacokinetic profile of SU was also investigated.